Setting a Mail Server is one of key requirements when starting any business. This could mean using mail solutions with SaaS offering or deploying a complete mail solution in your own infrastructure. Zimbra is a popular open source mail solution designed for use in small to large enterprises. There is a commercial offering of you want extra features. In this tutorial we will discuss how you can install configure Zimbra Mail Server on CentOS 8 and RHEL 8 Linux Server.

The main components of Zimbra Mail and Collaboration Server are:

  • Zimbra Core: These are basic libraries, utilities, monitoring tools, and basic configuration files.
  • Zimbra LDAP: This has the OpenLDAP LDAP directory server that provides authentication and configs store for users and other zimbra components.
  • Zimbra MTA (mail routing server): Has Postfix mail transfer agent (MTA) that receives email via SMTP and routes each message to the appropriate Zimbra mailbox server using Local Mail Transfer Protocol (LMTP). It also includes the anti-virus and anti-spam components.
  • Zimbra Store (Zimbra server): The mailbox server includes Data store, Message store and Index store for the mailboxes on the server. When a mail arrives, the Zimbra server schedules a thread to have the message indexed in the index store.
  • Zimbra-SNMP: This is an optional component for for monitoring and it runs on every server (Zimbra server, Zimbra LDAP, Zimbra MTA). Swatch is used to watch the syslog output to generate SNMP traps.
  • Zimbra Logger: This is an optional component for the mailbox server. It installs tools for syslog aggregation, reporting, and message tracing. This is required for the message trace feature.

See below system Architecture for how all the components work together to deliver a collaboration suite.

zimbra server architecture

Install Zimbra Mail Server on CentOS 8 | RHEL 8

As of this article writing the latest Zimbra collaboration suite release is version 9 but not available in open source offering yet. This is the Zimbra Mail Server we’ll install in our CentOS 8 | RHEL 8 server. Follow the steps below to install and configure Zimbra Mail Server on CentOS 8 / RHEL 8 Linux system.

The minimum system requirements for this installation are:

  • Memory: >=8GB
  • vcpus: >=4
  • Disk: /opt >10GB – Recommended to have /opt/zimbra as a separate partition.
  • Mail Domain: FQDN with configured DNS entry for MX, e.g
  • DNS A record for MX entry

This is what I have on my Server:

$ free -h
              total        used        free      shared  buff/cache   available
Mem:           15Gi       169Mi        14Gi        16Mi       206Mi        14Gi
Swap:            0B          0B          0B

$ df -hT /opt
Filesystem     Type  Size  Used Avail Use% Mounted on
/dev/sda1      ext4  151G 1020M  143G   1% /

Step 1: Update System, install dependencies and configure NTP

As we always do ensure the system is updated to the latest available OS release.

sudo dnf -y update

Install few basic dependencies.

sudo dnf -y install epel-release dnf-utils
sudo dnf config-manager --enable PowerTools
sudo dnf -y install bash-completion vim curl wget unzip openssh-clients telnet net-tools sysstat perl-core libaio nmap-ncat bind-utils tar

Set server hostname to match Mail Server DNS name:

sudo hostnamectl set-hostname --static

Also configure correct timezone and NTP.

sudo dnf -y install chrony
sudo timedatectl set-timezone Africa/Nairobi
sudo systemctl enable --now chronyd
sudo chronyc sources

Confirm time is correctly set.

$ timedatectl
               Local time: Sun 2020-07-05 14:47:26 EAT
           Universal time: Sun 2020-07-05 11:47:26 UTC
                 RTC time: Sun 2020-07-05 11:47:25
                Time zone: Africa/Nairobi (EAT, +0300)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

Perform a system reboot to ensure the server can reboot after the upgrades.

sudo systemctl reboot

Step 2: Configure DNS entries.

We’ll need to set two DNS records.

  1. An A record for the Mail Server
  2. An MX record

These are the values I’ll be setting for my Zimbra Server A MX MX

My DNS provider is Cloudflare. Please consult your DNS provider on how to configure A and MX records.

Setting A record:

zimbra mail server set a record

Set MX record for primary domain.

zimbra mail server set mx record

Also set MX record for Mail Server.

zimbra mail server set mx record 02

Give it few minutes to propagate then validate the settings on Zimbra server command line.

$ dig A +short

$ dig MX +short

$ dig MX +short

Step 3: Download Zimbra Collaboration Software

There are two editions of Zimbra Collaboration suite:

In this guide we’ll install the open source edition of Zimbra on CentOS 8 | RHEL 8 Linux server.


Extract file:

tar xvf zcs-8.8.15_GA_3953.RHEL8_64.20200629025823.tgz

Step 4: Install Zimbra Collaboration Suite on CentOS 8 | RHEL 8

Add your Server IP and DNS name to /etc/hosts file.

$ sudo vim /etc/hosts

Ensure locale is set correctly – Mine is for US English and UTF-8:

sudo localectl set-locale LANG=en_US.UTF-8
sudo localectl set-locale LANGUAGE=en_US
echo "export LC_ALL=en_US.UTF-8" >>~/.bashrc

Log in back to the Zimbra server and cd to the directory where the ZCS archive tar file is saved.

cd zcs-8.8.15_GA_3953.RHEL8_64.20200629025823

In the directory you’ll see:

  • README.txt – The readme file
  • – install script
  • bin/ – binaries used during install
  • data/ – contains installation data
  • packages/ – contains ZCS rpms
  • docs/ – more documentation

We will begin the installation by running script.

sudo ./

1. Type “Y” to accept license terms and start the installation.

Do you agree with the terms of the software license agreement? [N] Y

2. Agree to use Zimbra package repository.

Use Zimbra's package repository [Y] y
Importing Zimbra GPG key

Configuring package repository

Checking for installable packages

Found zimbra-core (local)
Found zimbra-ldap (local)
Found zimbra-logger (local)
Found zimbra-mta (local)
Found zimbra-dnscache (local)
Found zimbra-snmp (local)
Found zimbra-store (local)
Found zimbra-apache (local)
Found zimbra-spell (local)
Found zimbra-memcached (repo)
Found zimbra-proxy (local)
Found zimbra-drive (repo)
Found zimbra-imapd (local)
Found zimbra-patch (repo)
Found zimbra-mta-patch (repo)
Found zimbra-proxy-patch (repo)

3. Select the packages to install

Install zimbra-ldap [Y]
Install zimbra-logger [Y]
Install zimbra-mta [Y]
Install zimbra-dnscache [Y]
Install zimbra-snmp [Y]
Install zimbra-store [Y]
Install zimbra-apache [Y]
Install zimbra-spell [Y]
Install zimbra-memcached [Y]
Install zimbra-proxy [Y]
Install zimbra-drive [Y]
Install zimbra-imapd (BETA - for evaluation only) [N]

Install zimbra-chat [Y]
Checking required space for zimbra-core
Checking space for zimbra-store
Checking required packages for zimbra-store
zimbra-store package check complete.


The system will be modified.  Continue? [N] Y

Download and installation of Zimbra packages will start.x

Downloading packages (11):

Removing /opt/zimbra
Removing zimbra crontab entry...done.
Cleaning up zimbra init scripts...done.
Cleaning up /etc/security/limits.conf...done.

Finished removing Zimbra Collaboration Server.

Installing repo packages (11):

Installing local packages (26):

Installing extra packages (5):

Running Post Installation Configuration:
Operations logged to /tmp/zmsetup.20200705-161319.log
Installing LDAP configuration database...done.
Setting defaults...

Set Mail Domain when you get DNS error to the primary domain that we added DNS entry for.

DNS ERROR resolving MX for
It is suggested that the domain name have an MX record configured in DNS
Change domain name? [Yes]
Create domain: []
	MX: (

Set Admin account password – 7>4

Main menu

   1) Common Configuration:
   2) zimbra-ldap:                             Enabled
   3) zimbra-logger:                           Enabled
   4) zimbra-mta:                              Enabled
   5) zimbra-dnscache:                         Enabled
   6) zimbra-snmp:                             Enabled
   7) zimbra-store:                            Enabled
        +Create Admin User:                    yes
        +Admin user to create:                 [email protected]
******* +Admin Password                        UNSET
        +Anti-virus quarantine user:           [email protected]
        +Enable automated spam training:       yes
        +Spam training user:                   [email protected]
        +Non-spam(Ham) training user:          [email protected]
        +SMTP host:                  
        +Web server HTTP port:                 8080
        +Web server HTTPS port:                8443
        +Web server mode:                      https
        +IMAP server port:                     7143
        +IMAP server SSL port:                 7993
        +POP server port:                      7110
        +POP server SSL port:                  7995
        +Use spell check server:               yes
        +Spell server URL:                     //
        +Enable version update checks:         TRUE
        +Enable version update notifications:  TRUE
        +Version update notification email:    [email protected]
        +Version update source email:          [email protected]
        +Install mailstore (service webapp):   yes
        +Install UI (zimbra,zimbraAdmin webapps): yes

   8) zimbra-spell:                            Enabled
   9) zimbra-proxy:                            Enabled
  10) Default Class of Service Configuration:
   s) Save config to file
   x) Expand menu
   q) Quit

Address unconfigured (**) items  (? - help) 7

Store configuration

   1) Status:                                  Enabled
   2) Create Admin User:                       yes
   3) Admin user to create:                    [email protected]
** 4) Admin Password                           UNSET
   5) Anti-virus quarantine user:              [email protected]
   6) Enable automated spam training:          yes
   7) Spam training user:                      [email protected]
   8) Non-spam(Ham) training user:             [email protected]
   9) SMTP host:                     
  10) Web server HTTP port:                    8080
  11) Web server HTTPS port:                   8443
  12) Web server mode:                         https
  13) IMAP server port:                        7143
  14) IMAP server SSL port:                    7993
  15) POP server port:                         7110
  16) POP server SSL port:                     7995
  17) Use spell check server:                  yes
  18) Spell server URL:                        //
  19) Enable version update checks:            TRUE
  20) Enable version update notifications:     TRUE
  21) Version update notification email:       [email protected]
  22) Version update source email:             [email protected]
  23) Install mailstore (service webapp):      yes
  24) Install UI (zimbra,zimbraAdmin webapps): yes

Select, or 'r' for previous menu [r] 4
Password for [email protected] (min 6 characters): [8IFLmFH7Wr] <Enter-or-set-your-own-password>

Return to previous menu and hit the a key to begin installation.

Select, or 'r' for previous menu [r] r

Main menu

   1) Common Configuration:
   2) zimbra-ldap:                             Enabled
   3) zimbra-logger:                           Enabled
   4) zimbra-mta:                              Enabled
   5) zimbra-dnscache:                         Enabled
   6) zimbra-snmp:                             Enabled
   7) zimbra-store:                            Enabled
   8) zimbra-spell:                            Enabled
   9) zimbra-proxy:                            Enabled
  10) Default Class of Service Configuration:
   s) Save config to file
   x) Expand menu
   q) Quit

*** CONFIGURATION COMPLETE - press 'a' to apply
Select from menu, or press 'a' to apply config (? - help) a
Save configuration data to a file? [Yes]
Save config in file: [/opt/zimbra/config.9721]
Saving config in /opt/zimbra/config.9721...done.
The system will be modified - continue? [No] yes

The installer script will start to configure Zimbra Mail Server on CentOS 8 | RHEL 8. If the installation was successful you’ll receive an output similar to below.

Operations logged to /tmp/zmsetup.20200705-161319.log
Setting local config values...done.
Initializing core config...Setting up CA...done.
Deploying CA to /opt/zimbra/conf/ca ...done.
Creating SSL zimbra-store certificate...done.
Creating new zimbra-ldap SSL certificate...done.
Creating new zimbra-mta SSL certificate...done.
Creating new zimbra-proxy SSL certificate...done.
Installing mailboxd SSL certificates...done.
Installing MTA SSL certificates...done.
Installing LDAP SSL certificate...done.
Installing Proxy SSL certificate...done.
Initializing ldap...done.
Setting replication password...done.
Setting Postfix password...done.
Setting amavis password...done.
Setting nginx password...done.
Setting BES searcher password...done.
Creating server entry for
Setting Zimbra IP Mode...done.
Saving CA in ldap...done.
Saving SSL Certificate in ldap...done.
Setting spell check URL...done.
Setting service ports on
Setting zimbraFeatureTasksEnabled=TRUE...done.
Setting zimbraFeatureBriefcasesEnabled=TRUE...done.
Checking current setting of zimbraReverseProxyAvailableLookupTargets
Querying LDAP for other mailstores
Searching LDAP for reverseProxyLookupTargets...done.
Adding to zimbraReverseProxyAvailableLookupTargets
Setting Master DNS IP address(es)...done.
Setting DNS cache tcp lookup preference...done.
Setting DNS cache udp lookup preference...done.
Setting DNS tcp upstream preference...done.
Updating zimbraLDAPSchemaVersion to version '1571057268'
Setting TimeZone Preference...done.
Disabling strict server name enforcement on
Initializing mta config...done.
Setting services on
Adding to zimbraMailHostPool in default COS...done.
Creating domain
Setting default domain name...done.
Creating domain exists.
Creating admin account [email protected]
Creating root alias...done.
Creating postmaster alias...done.
Creating user [email protected]
Creating user [email protected]
Creating user [email protected]
Setting spam training and Anti-virus quarantine accounts...done.
Initializing store sql database...done.
Setting zimbraSmtpHostname for
Configuring SNMP...done.
Setting up syslog.conf...done.
Starting servers...done.
Installing common zimlets...
Finished installing common zimlets.
Restarting mailboxd...done.
Creating galsync account for default domain...done.

You have the option of notifying Zimbra of your installation.
This helps us to track the uptake of the Zimbra Collaboration Server.
The only information that will be transmitted is:
	The VERSION of zcs installed (8.8.15_GA_3953_RHEL8_64)
	The ADMIN EMAIL ADDRESS created ([email protected])

Notify Zimbra of your installation? [Yes]
Notify Zimbra of your installation? [Yes]
Notifying Zimbra of installation via[email protected]

Notification complete

Checking if the NG started running...done.
Setting up zimbra crontab...done.

Moving /tmp/zmsetup.20200705-161319.log to /opt/zimbra/log

Configuration complete - press return to exit

Confirm Zimbra services status.

$ sudo su - zimbra -c "zmcontrol status"
	amavis                  Running
	antispam                Running
	antivirus               Running
	dnscache                Running
	ldap                    Running
	logger                  Running
	mailbox                 Running
	memcached               Running
	mta                     Running
	opendkim                Running
	proxy                   Running
	service webapp          Running
	snmp                    Running
	spell                   Running
	stats                   Running
	zimbra webapp           Running
	zimbraAdmin webapp      Running
	zimlet webapp           Running
	zmconfigd               Running

Step 5: Configure SSL Certificate

It is recommended to use SSL certificate signed by certified CA or free Let’s Encrypt Certificate. Checkout our guide below for the installation.

Secure Zimbra Server with Let’s Encrypt SSL Certificate

Step 6: Accessing Zimbra Admin Dashboard

If you have an active firewall, check our guide on opening ports:

Zimbra Firewall Configuration with Ufw & Firewalld

Now that our installation of Zimbra on CentOS 8 | RHEL 8 is complete let’s open the Admin console https://ip-addres|hostname:7071

zimbra login dashboard

Login with Username admin and Password configured earlier.

zimbra mail server loggedin

Confirm all Zimbra services are in running state under the “Monitor” section.

zimbra mail server service status

More guides on Zimbra:

How To Restore Zimbra LDAP database from Backup

How To Configure Microsoft Outlook for Zimbra

How To Set Secure Password Policy on Zimbra

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